- B-58, Sector E Aliganj, Lucknow, Uttar Pradesh – 226024 , India
- info@tajallitech.com
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Secondary Injection Testing
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Secondary Injection Testing
What is Secondary Injection Testing?
ETU etc.) on a circuit breaker and injecting a simulated current to prove it works at different levels. Why is it important to Secondary Injection Test Trip Units during a breaker service?
The trip unit on a low voltage breaker (molded case or air type) is usually an option selected by the system or panel designer to provide protection to the site in the event of a fault or over current occurring. The trip unit measures the amount of current and calculates its effect on the site system against its settings (usually decided by a commissioning Engineer), and will trip or open the breaker as required. The larger the current measured, the quicker the breaker should trip or open.
It is an important test to carry out on a trip unit during a service. By connecting one of our many different manufacturers secondary injection test sets we can ensure that the trip unit, its settings or factory parameters, and associated components are working as they should do. It is also a key test for a circuit breaker after a mechanical service and inspection, as the breaker is repeatedly charged, closed and opened. These sequences help ensure key lubrication has worked into the mechanisms that are often found dry and un-serviced. The test equipment types, and designs, vary greatly but all are designed to prove the breaker protection from very simple to complex methods. Tests normally carried out, dependent on the specification of trip unit and tester are:
- Long Time
- Short Time
- Instantaneous
- Ground Fault
- Earth Leakage
Each of these tests are repeated several times, to ensure reliable, repeatable, operation and trip times. Any inconsistence could imply the trip unit is not working correctly hence not protecting the site systems.
Tajalli Tech is continually assessing customer and site requirements and invests in old and new secondary injection test equipment every year. We pride ourselves on having a substantial range of key current, and obsolete, manufacturer test equipment that is maintained and calibrated for our use on site and in our workshop. On occasion where the breaker is obsolete and equipment is not available we use, where possible, our secondary injection tester to test breaker protection.
What is Primary Injection Testing?
Primary Injection Testing is where an actual current is applied to a breaker to check its protection. This test is usually done, on low voltage switchgear, in the manufacturers facility only. This testing can be done on site but requires further heavy test equipment to generate the currents required to test protection; hence the importance and availability of secondary injection testing. If you require primary injection testing please contact us for further details. Please contact us for you specific requirements or if you have any questions we can help with.
Protection relay testing
Secondary injection testing of protection relays
A protection relay that is set wrongly, or has failed silently, will not trip your breaker during a fault. Secondary injection testing checks each relay by feeding it test currents and voltages from a portable test kit, and confirms it trips at the right value and time.
We test numerical and electromechanical relays, and we can also do primary injection tests of CTs and the complete protection circuit.
Relays and functions we test
- Overcurrent and earth fault (50/51, 50N/51N)
- Differential protection (87)
- Distance protection (21)
- Directional overcurrent (67)
- Under and over voltage (27/59)
- Thermal overload (49)
- Restricted earth fault (REF)
- ACB and MCCB electronic trip units
- CT ratio and polarity, and primary injection
- Trip circuit and breaker operation check
How we work
1
Collect settings
We take the relay settings and the single-line diagram.
2
Plan
Isolation and test sequence agreed with your team.
3
Test
Pick-up, timing and characteristic tests on every relay.
4
Report
Results against settings, with any corrections needed.
Why Tajalli Tech
Since 2016Class-A licensed electrical contractor based in Aliganj, Lucknow.
Calibrated test kitsOur own instruments, with a written report after every job.
ISO 9001:2015Documented quality process, and a Schneider Electric EcoXpert partner for LV services.
Questions
What is the difference between secondary and primary injection?
Secondary injection tests the relay by injecting current directly into it. Primary injection passes current through the CT primary, so it checks the CT, wiring and relay together.
How often should relays be tested?
Once a year, after any change in settings, and after a relay has operated on a fault.
Do you test numerical relays?
Yes. We test numerical relays of common makes and can check or apply settings as per your coordination study.
Will we get a test report?
Yes. Every relay is reported with its settings, the test values and the measured trip times.
Book relay testing
Tell us the number of relays and send the settings if you have them. We will quote and plan the visit.
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